now it is throwing up an error saying it can't find the file movies\whatever\VIDEO_TS, please make sure the drive is correctly connected.
That doesn't sound like a message from Coollector, more like a message from your media player.
It seems as though it's now trying to select the folder as a file to pass to the media player, rather than passing the whole folder
I don't have any VIDEO_TS folders on my computer. Please allow me a little time to rip a DVD and test it.
On a possibly related note, it doesn't seem possible to manually associate a VIDEO_TS folder with a movie in the database; when you navigate to and select the VIDEO_TS folder in the dialog, it just opens the folder with the bup,ifo etc. files inside, rather than recognising it as a 'movie file' in it's own right. I'm sure it used to be possible as I have some files that have been manually added like this; it may just be that I can't remember the correct procedure, of course.
I don't think it is or has ever been possible to associate a VIDEO_TS manually as the dialog which is opened is a file select dialog (not a folder select dialog). Your VIDEO_TS folders must have been associated during a disk scanning.